1. Field of the Invention
This invention relates to a camera provided with eye-gaze detecting means suitable for use, for example, in a camera such as a still camera or a video movie camera endowed with the function of detecting an eye-gaze position in the photographing picture plane (of various positions in the photographing plane, the position of the portion the user is gazing at) and controlling the auto focusing operation of a photo-taking lens or controlling the exposure of film or an image pickup element.
2. Related Background Art
As cameras of this kind, there are known cameras in which what portion in the photographing picture plane the photographer should recognize as the main object is determined on the basis of the result of the eye-gaze detection and a photo-taking lens is driven by the use of an information value representative of the focus detection state corresponding to the object in the determined portion to thereby effect so-called auto focusing. There are also known cameras in which automatic exposure control is effected by the use of an information value representative of the luminance of an object in the portion recognized as the main object on the basis of the eye-gaze detection (such cameras are disclosed, for example, in Japanese Laid-Open Patent Application No. 63-94232, Japanese Laid-Open Patent Application No. 1-241511 and Japanese Laid-Open Patent Application No. 2-5).
However, in a camera wherein auto focusing is effected on the basis of the result of the eye-gaze detection, there may arise a problem as will be described below.
Suppose a case where, as shown in FIG. 7 of the accompanying drawings, a plurality of focus detection areas 1-3 are set in the photographing picture plane 10. Also assume that when the photographer gazes at between the focus detection area 1 and the focus detection area 2, the focus detection area nearer to the eye-gaze point is selected and a photo-taking lens is driven on the basis of an information value representative of the focus detection state in that area. Assuming that in the case of such a camera, the photographer's eye-gaze point is near the intermediate point a between the focus detection area 1 and the focus detection area 2 and, as shown in FIG. 8 of the accompanying drawings, the object distance D1 in the area 1 and the object distance D2 in the area 2 differ greatly from each other, the selected focus detection area will change over from the area 1 to the area 2 or from the area 2 to the area 1 simply if the eye-gaze point slightly moves unconsciously to right and left near the point a (the gaze of the human eye moves involuntarily even if one is gazing at one point). Each time the changeover takes place, the photo-taking lens is reciprocally driven between driven positions R1 and R2 as shown in FIG. 9 of the accompanying drawings, and this results in the waste of electric power. This is a problem which will likewise arise when the vicinity of the intermediate point b between the focus detection areas 2 and 3 is gazed at. Also, if the eye-gaze point is moved from the left end to the right end of the picture plane or conversely, the selected focus detection area will change over when the eye-gaze passes the point a and the point b and therefore, in conformity therewith, the driving of the photo-taking lens will take place suddenly. Thus, in the case of a camera for photographing moving images like a video movie camera, the object distance focused in a photographed moving image varies suddenly and therefore, that moving image becomes very unnatural one.
On the other hand, in a camera wherein automatic exposure is effected on the basis of the result of the eye-gaze detection, there may arise, for example, a problem as will be described below.
Assume that where as shown in FIG. 10 of the accompanying drawings, a plurality of photometry areas 11-13 are set in the photographing picture plane 10, a photometry area corresponding to the photographer's eye-gaze point is selected and exposure is determined on the basis of the luminance information in that area. In the case of such a camera, assuming that the photographer's eye-gaze point is near the intermediate point a between the photometry area 11 and the photometry area 12 and, as shown in FIG. 11 of the accompanying drawings, the object luminance B1 in the area 11 and the object luminance B2 in the area 12 differ greatly from each other, the selected photometry area will change over from the area 11 to the area 12 or from the area 12 to the area 11 simply if the eye-gaze point slightly moves unconsciously to right and left near the point a. Accordingly, simply if in spite of having gazed at a single object present near the eye-gaze point a, the photographer slightly moves the eye-gaze point, the exposure amount as the result of automatic exposure control may greatly vary to E1 and E2 as shown in FIG. 12 of the accompanying drawings. This is a problem which will likewise arise when the vicinity of the intermediate point b between the photometry areas 12 and 13 is gazed at. Also, if the eye-gaze point is moved from the left end to the right end of the picture plane or conversely, the selected photometry area will change over when the eye-gaze passes the point a and the point b and therefore, in conformity therewith, the exposure amount controlled will vary suddenly. Thus, in the case of a camera for photographing moving images like a video movie camera, the brightness of photographed moving images varies suddenly and unnaturally.